KR101656930B1 - Stirred tank reactor and meth1od for preparing pvc resin using th1e same - Google Patents

Abstract

The present invention relates to a stirring tank reactor and a production method of the PVC resin using the same. According to the present invention, there is provided an agitation tank reactor which is economical and excellent in the effect of reducing the foam layer, and a method for producing a PVC resin using the same.

Description

TECHNICAL FIELD The present invention relates to a stirrer tank reactor and a method of manufacturing the same. More particularly, the present invention relates to a stirrer tank reactor,

The present invention relates to a stirrer tank reactor and a method of manufacturing a PVC resin using the same, and more particularly, to a stirrer tank reactor which is economical and has an excellent foam layer reducing effect, and a method for producing a PVC resin using the same.

In the reactor, the impeller is a part that mixes the liquid directly by changing the mechanical power to the agitation energy. Each one from the shape of the impeller to the rotational balance are factors affecting the stirring efficiency. Particularly, in the case of high-speed rotation or medium-speed rotation, the shape of the impeller greatly affects the stirring performance. For the reactants containing liquid phases of different phases, in the existing studies, the homogeneous particle states were obtained by adjusting the type, shape, angle and speed of the impeller in the reactor to obtain products having the optimum particle size distribution and particle shape Respectively.

However, when the polymerization is carried out at a high temperature, the foam and the light PVC particles rise up to the reflux condenser, causing some re-polymerization, thereby generating large particles or generating a large scale.

In addition, the upper impeller was designed to be small in order to increase the force pushing the fluid from the lower part of the agitation tank to the upper part by using a batch type reactor or when the specific gravity difference is large. Conversely, It was confirmed that the agitating force sufficient to evenly mix the layer to the lower portion of the reactor could not be secured.

On the other hand, when the lower impeller is provided at the lowermost stage of the stirring tank, before the product volume in the stirring tank is filled, the lower interfacial collision force and the P / V value increase, Disadvantages were also identified.

Various techniques for reducing such a foam layer or for suppressing the formation of a foam layer have been applied, but there is still a need for a technology that is excellent in economical efficiency and excellent in the effect of reducing the foam layer.

In order to solve the problems of the prior art as described above, the present inventors have found that by controlling the positions of the lower end and the upper end of the impeller so that the upper flow velocity becomes faster than the lower flow velocity under the same rotation condition, By reducing the upper vortex by increasing the downward force and by adjusting the position of the lower impeller, it was possible to reduce the fine particles, increase the particle size, and increase the uniformity. The foam layer, which has risen to the reflux condenser, The present invention has been accomplished on the basis of confirming the effect of effectively reducing the amount of the catalyst without applying the injection or foaming prevention technique.

That is, the present invention aims to provide an agitating tank reactor which is economical and excellent in the effect of reducing the foam layer, and a process for producing a PVC resin using the same.

In order to achieve the above object, the present invention is a Stirred Tank Reactor including a two-stage impeller stirrer, wherein a reflux condenser is coupled to an upper portion of the stirring tank,

(H1 / D) of the height (h1) of the two-stage impeller stirrer to the impeller at the lower end spaced from the bottom surface of the stirring tank to the inner diameter (D) of the stirring tank is 0.11 to 0.17, Wherein a ratio (h2 / D) of an interval (h2) between the lower end and the upper impeller of the two-stage impeller stirrer to the inner diameter (D) of the stirring tank is in the range of 0.61 to 0.67, or 0.78 to 0.84. Lt; / RTI >

In addition, the present invention provides a method for producing a PVC resin, comprising polymerizing a vinyl chloride monomer using the stirring tank reactor.

According to the present invention, there is provided an agitating tank reactor which is economical and excellent in the foam layer reducing effect, and a method of producing a PVC resin using the same.

1 is a view schematically showing a conventional two-stage impeller stirrer.
2 is a schematic view of a stirring tank reactor including a two-stage impeller stirrer according to the present invention.

Hereinafter, the present invention will be described in detail with reference to FIG.

The stirrer tank reactor of the present invention is characterized in that a reflux condenser (not shown) is coupled to the upper portion of the stirring tank 10 and the distillation condenser (not shown) is separated from the bottom surface of the stirring tank 10 (H1 / D) of the height h1 to the lower end impeller 14 to the inner diameter D of the stirring tank 10 is 0.11 to 0.17, and the lower end 14 of the two-stage impeller stirrer 14 (H2 / D) of the distance (h2) between the upper portion (13) and the impeller of the upper portion (13) to the inner diameter (D) of the stirring tank is in the range of 0.61 to 0.67 or 0.78 to 0.84.

The stirring tank reactor may be, for example, a polymerization reactor.

The reactor for polymerization may be, for example, a reactor for the present carbon-to-carbon bond reaction of a vinyl chloride monomer, and has the effect of producing a PVC resin which is advantageous in production and quality of soft and hard products .

The impeller may be, for example, a pfaudler type, a pitch 1 paddle type, a pitch turbine type, or the like.

The impeller may be, for example, a U-shaped, V-shaped, or a mixture thereof, around a stirrer shaft.

The impeller can be, for example, 2 to 5, 2 to 4, or 3, respectively.

 The lower impeller 14 may be positioned on the same plane as the lower end of the inner wall, for example.

In addition, one impeller may be further included between the upper impeller 13 and the lower impeller 14.

The reflux condenser (not shown) repeats the process of condensing the vaporized solvent during the reaction and returning it to the lower side of the reactor, thereby efficiently controlling the heat generated during the polymerization, Even when polymerization is carried out at different temperatures, a product characteristic of a similar tendency can be realized.

The stirring tank reactor may further include a baffle (not shown) and a jacket (not shown), in which case it can be combined with a reflux condenser (not shown) to have more heat removal range, So that it is possible to respond to a relatively high temperature or a large amount of heat.

The baffle and jacket are not normally limited to baffles and jackets that can be installed in a stirred tank reactor.

The ratio of the inner diameter (B) of the baffle to the inner diameter (D) of the stirring tank (10) may be, for example, in the range of 0.1 to 0.2 .

The stirring tank 10 may include a reaction material inlet pipe (not shown) at its upper portion and a discharge member 11 including a product discharge pipe at its bottom surface.

In the present invention, descriptions of apparatuses, means, etc., which are not particularly limited, are included in a conventional stirring tank reactor such as a power unit for a stirrer and the like.

The ratio h1 / D of the height h1 from the bottom surface of the stirring tank 10 to the bottom impeller 14 provided to the bottom surface of the stirring tank 10 to the inner diameter D of the stirring tank 10 is 0.11 - 0.17. Within this range, there is an effect of reducing fine particles, increasing particle size, and increasing uniformity.

The height h1 may be a height from the axis 12 provided on the discharge member 11 provided on the bottom surface of the stirring tag 10 to the lower impeller 14. [

As another example, the ratio (h2 / D) of the distance h2 between the lower impeller 14 and the upper impeller 13 of the two-stage impeller stirrer to the inner diameter D of the stirring tank 10 is preferably 0.61 to 0.67 Or within the range of 0.78 to 0.84. In this range, the mixing time of the upper material (mixture) and the lower material (mixture) is greatly shortened and the agitating force is increased, There is a beneficial effect.

The stirring tank may have a height h1 from the axis 12 disposed on the discharge member 11 provided at the bottom of the stirring tank 10 to the lower impeller 14 spaced from the stirrer shaft The ratio of the length L of the shaft 15 to the length L of the shaft 15 may be 0.70 to 0.10.

In the two-stage impeller stirrer, the ratio (h2 / L) of the distance h2 between the lower impeller 14 and the upper impeller 13 to the length L of the shaft 15 is 0.36 to 0.40, 0.46 to 0.50. Within this range, it is effective to reduce the upper bubble by lowering the foam layer generated in the polymerization to the lower part.

The ratio d1 / D, d2 / D of the widths d1 and d2 of the two-stage impeller stirrers 13 and 14 to the inner diameter D of the stirring tank 10 is, for example, Can be 0.42 to 0.45, respectively. Within this range, the vinyl chloride monomer condensed at the upper part of the reflux condenser is uniformly mixed to the lower part of the stirring tank, and the foaming layer rising to the reflux condenser is lowered.

The method for producing the PVC resin according to the present invention is characterized by comprising the step of polymerizing the vinyl chloride monomer using the stirring tank (10) reactor of the present invention.

The polymerization can be carried out in suspension, for example. In this case, PVC resin having an apparent specific gravity low and a high plasticizer efficiency is advantageous in producing soft and hard products and in quality.

The suspension polymerization can be carried out, for example, at 40 to 85 캜, 50 to 75 캜, or 58 to 68 캜.

The method for producing the PVC resin may be, for example, to produce PVC having a polymerization degree of 700 to 1000.

The PVC resin may be prepared by, for example, recovering unreacted monomers after the suspension polymerization, removing unreacted monomers, and dehydrating and drying the obtained slurry.

1 is a schematic view of a conventional two-stage impeller stirrer, in which a shaft 15 and a top impeller 13 and a bottom impeller 14 coupled thereto are shown, The ratio h2 / D of the inner diameter D of the reactor to the distance h2 between the upper and lower ends of the impeller 13 and 14 is 0.78 to 0.84 and the axial number 12 provided on the discharge member 11 provided on the bottom surface, The ratio of the height h1 of the lower impeller 14 to the length L of the stirrer shaft 15 is 0 and the widths d1 and d2 of the two- D is the ratio of the inner diameter D of the stirring tank 10 to d1 / D is 0.40 to 0.42, and d2 / D is 0.42 to 0.45.

FIG. 2 is a schematic view of a stirring tank reactor including a two-stage impeller stirrer according to the present invention. In the reactor, a shaft 15 and a top impeller 13 and a bottom impeller 14, And a discharge member 11 is provided on the bottom surface of the reactor so that the axial flow 12 of the shaft 15 is spaced apart from the bottom surface by the height h1 from the bottom surface to the bottom impeller 14, Respectively.

The ratio h2 / D of the reactor inner diameter D of the stirring tank 10 to the gap h2 between the upper and lower stage impellers 13 and 14 is 0.78 to 0.84, The ratio of the height h1 of the shaft 12 to the lower impeller 14 to the length L of the stirrer shaft 15 is 0.06 to 0.10, (D1 / D, d2 / D) of the widths d1 and d2 of the stirring tank 10 to the inner diameter D of the stirring tank 10 are respectively 0.42 to 0.45.

The discharge member may be, for example, a blowdown device.

The blowdown device can be connected to a blowdown tank, for example, in which case the polymerized resin can be transferred from the stirred tank reactor to the blowdown tank by opening the discharge valve of the blowdown device after polymerization.

The blowdown device, the blowdown tank, the slurry tank, or the pipe connecting them may be provided with a vent and a pump capable of discharging gas. The blow-down tank is not particularly limited in the case of a blow-down tank which can be usually used in a polymer production process.

The shaft 12 of the shaft 15 may be located on the same line as the discharge member 11, for example.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention within the scope and spirit of the following claims, Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example 1

2, a two-stage impeller (not shown) having a reflux condenser (not shown) and h1 of 100-150 mm, h2 of 700-750 mm, d1 of 380-400 mm, d2 of 380-400 mm, D of 897 mm and L of 1498 mm A stainless steel polymerization reactor (h1 / D = 0.11 to 0.17, h2 / D = 0.78 to 0.84, d1 / D = 0.42 to 0.45) having a stirrer (13, 14) , polyvinyl alcohol having a degree of hydration of 88%, 0.05 part of polyvinyl alcohol having a degree of hydration of 72%, 0.02 part of polyvinyl alcohol having a degree of hydration of 72%, polyvinyl alcohol having a degree of hydration of 55% 0.015 parts by weight of alcohol, 0.005 parts by weight of hydroxypropyl methylcellulose and 0.088 parts by weight of t-butyl peroxyneodecanonate (BND) were charged. Then, the inside was degassed with a vacuum pump while stirring, and 90 parts by weight of vinyl chloride monomer Respectively.

The reaction was continued while keeping the temperature of the polymerization reactor at 58 캜 throughout the reaction, and 10 parts by weight of vinyl chloride monomer was further added at 50% of the total polymerization time.

The polymerization was stopped when the polymerization reactor pressure was changed to 1.0 kg / cm ² . After adding 0.05 part by weight of triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] as an antioxidant, unreacted monomers were recovered, And recovered in a polymerization reactor in a slurry state. The slurry thus obtained was dried in a fluidized bed drier by a conventional method to obtain a vinyl chloride polymer (PVC resin) having a degree of polymerization of 1000.

Example 2

In the same manner as in Example 1 except that h2 in Example 1 was 550-600 mm (h2 / D = 0.61-0.67) and the reaction was carried out while maintaining the temperature of the polymerization reactor at 68 캜 throughout the reaction A PVC resin with a degree of polymerization of 700 was prepared.

Comparative Example 1

A PVC resin having a degree of polymerization of 1000 was prepared in the same manner as in Example 1 except that h1 was 0 mm (h1 / D = 0).

 [Test Example]

The properties of the PVC resin prepared in Examples 1 to 2 and Comparative Example 1 were measured by the following methods, and the results are shown in Table 1 below.

* Average particle size: Measured according to ASTM D 1243-79.

Fine (200 mesh1): Measured by the ASTM D 1243-79 method.

* Apparent Specific Gravity (g / cc): Measured according to ASTM D 1895-89.

* Plasticizer Absorption Rate (wt%): The amount of DOP absorbed by the sample in accordance with ASTM D 3367-95 was measured in terms of wt% with respect to the weight of the sample before absorption.

* Foam level (%): Measured with a needle-shaped foam detector near the rounded Eclipse at the top of the reactor.

d1 / D, d2 / D 0.42 to 0.45 0.42 to 0.45 0.42 to 0.45 Item Example 1 Example 2 Comparative Example 1 Polymerization temperature (캜) 58 68 58 Impeller height ratio (h1 / D) 0.11-0.17 0.11-0.17 0 Impeller height ratio (h2 / D) 0.78 to 0.84 0.61 to 0.67 0.78 to 0.84 Defoamer type - - - Average particle diameter (占 퐉) 189 187 192 Fine (200 mesh,%) 0.5 0.6 3.2 Apparent Specific Gravity (g / cc) 0.578 0.557 0.583 Plasticizer absorption (wt%) 16.8 18.6 16.0 Form Level (%) 6 11 15

As shown in Table 1, when a PVC resin was produced using a stirring tank reactor including a two-stage impeller stirrer according to the present invention (Examples 1 and 2), the lower surface of the bottom of the stirring tank In the case where the impeller was not separated (Comparative Example 1), the grain size of the PVC resin was made small and the particle size distribution was narrowed due to an increase in contrast agglomeration force so that the amount of large particles or fine particles was finally reduced, And the plasticizer absorption rate was increased. In particular, it was confirmed that the foam level was reduced. It was confirmed that the physical properties of the resin can be significantly changed by controlling the position of the lower impeller in the case of the two stage impeller type reactor.

Particularly, in the case of Example 2 in which the interval between the upper and lower ends of the impeller is narrower than that of Example 1 having a wide gap, it is possible to provide a more improved resin.

Additional Experimental Example 1

A PVC resin having a degree of polymerization of 1000 was prepared in the same manner as in Example 1 except that h1 was 0 mm and d1 was 360 to 380 mm (h1 / D = 0, d1 / D = 0.40-0.42) (200 mesh), an apparent specific gravity of 0.565 g / cc, a plasticizer absorption rate of 17.3 wt%, and a foam level of 12% as measured in the same manner as in Example 1.

That is, in Example 1 in which a PVC resin was produced by using a stirring tank reactor including a two-stage impeller stirrer according to the present invention, the number of collisions between lower particles and the P / V value were reduced, The average grain size was increased due to the lumps of large particles, and the quality of the test was also increased. In Example 1, the flow rate of the upper impeller in the same rpm was further increased, and the force for lowering the expanded foam layer was increased. Thus, it was confirmed that the foam layer lowered in the polymerization was more effective in reducing the upper vortex.

Further Experimental Example 2

Example 1 was repeated except that the foaming was suppressed by collectively adding up to 100 ppm of the product name Siloxane LDC120A manufactured by Dow Corning Incorporated under the product name of Cognis Co. as the antifoaming agent every time the foam level was 70% A PVC resin having a degree of polymerization of 1,000 was prepared in the same manner as in Example 1 and the physical properties thereof were measured. As a result, the average particle size was 188 탆, Fine (200 mesh) 0.6%, apparent specific gravity 0.558 g / cc, plasticizer absorptivity 18.5 wt% The foam level was 11%.

That is, in Examples 1 and 2 in which a PVC resin was produced using a stirring tank reactor including a two-stage impeller stirrer according to the present invention, the addition of the defoamer No significant change in physical properties was observed as compared with Experiment 2, and no foam was improved in spite of the addition of defoamer. It was confirmed that the physical properties of the resin can be changed considerably by controlling the position of the impeller without injecting the defoamer in the case of the two stage impeller type reactor.

This is advantageous in terms of cost reduction since it can exhibit the same effect as the addition of defoamer without special additive, and it is also advantageous in that the reheat polymerization due to the foam rise or the clogging of the reflux condenser is retarded or delayed, .

10: stirring tank (reactor) 11: discharge member
12: Bearing number 14: Bottom impeller
13: upper impeller 15: stirrer shaft (shaft)

Claims (13)

A stirrer tank reactor comprising a two-stage impeller stirrer, wherein a reflux condenser is coupled to an upper portion of the stirring tank,
(H1 / D) of the height (h1) of the two-stage impeller stirrer to the impeller at the lower end spaced from the bottom surface of the stirring tank to the inner diameter (D) of the stirring tank is 0.11 to 0.17,
Wherein a ratio (h2 / D) of an interval (h2) between a lower end and an upper impeller of the two-stage impeller stirrer to an inner diameter (D) of the stirring tank is in a range of 0.61 to 0.67 or 0.78 to 0.84
Stirred tank reactor. The method according to claim 1,
Wherein the stirring tank reactor is a polymerization reactor
Stirred tank reactor. 3. The method of claim 2,
Characterized in that the reactor for polymerization is a reactor for suspension polymerization of a vinyl chloride monomer
Stirred tank reactor. The method according to claim 1,
The impeller may be a pfaudler type, a pitch 1 paddle type, or a pitch 1 turbine type.
Stirred tank reactor. The method according to claim 1,
The impeller is characterized by being U-shaped, V-shaped, or a mixture thereof, around a stirrer shaft
Stirred tank reactor. The method according to claim 1,
The stirrer tank is characterized in that a reactant inlet pipe is coupled to an upper portion and a product outlet pipe is coupled to a bottom surface
Stirred tank reactor. The method according to claim 1,
The stirring tank may have a ratio of a height h1 to a length L of a stirrer shaft from 0.07 to 0.10 from a bearing water provided on a discharge member provided on a bottom surface of a stirring tank to a lower- Featured
Stirred tank reactor. The method according to claim 1,
Wherein the two-stage impeller stirrer is characterized in that the ratio (h2 / L) of the distance (h2) between the lower and upper impellers to the length (L) of the shaft is in the range of 0.36 to 0.40 or 0.46 to 0.50
Stirred tank reactor. The method according to claim 1,
Wherein the ratio (d1 / D, d2 / D) of the width (d1, d2) of the two-stage impeller stirrer to the inner diameter (D) of the stirring tank is 0.42 to 0.45
Stirred tank reactor. The method according to claim 1,
Wherein the stirring tank is provided with a baffle therein
Stirred tank reactor. Characterized in that it comprises the step of polymerizing the vinyl chloride monomer using the stirring tank reactor of any one of claims 1 to 10
Method of making PVC resin. 12. The method of claim 11,
Characterized in that the polymerization is a suspension polymerization
Method of making PVC resin. 12. The method of claim 11,
The polymerization is characterized by producing a PVC having a degree of polymerization of 700 to 1000
Method of making PVC resin.

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